sub getmask { push(@sub, @ip); my $cnt = -1; foreach my $line (@mask) { $cnt++; if ($line != 255) { if ($flag > 0) { $sub[$cnt] = 0; } my $magic = 256 - $line; my $rem = $ip[$cnt] / $magic; $rem =~ s/\.(.+)//; $sub[$cnt] = $magic * $rem; } } print join(".", @sub);